How to Dump the Black Water Tank in Your 2020 Keystone Sprinter Limited 330KBS

If you own a 2020 Keystone Sprinter Limited 330KBS, you know how luxurious and well-equipped it is—right down to its advanced plumbing system. But even the best rigs need proper maintenance, especially when it comes to emptying the black water tank. Many new (and even seasoned) RVers find this task intimidating, messy, or confusing. You’re not alone. In fact, improper black tank dumping is one of the top causes of plumbing issues, odors, and costly repairs.

This guide walks you through the exact steps to safely and cleanly dump the black water tank in your 2020 Keystone Sprinter Limited 330KBS, with expert tips, best practices, and real-world troubleshooting advice. Let’s make this routine chore quick, odor-free, and stress-free.

Why Is Proper Black Water Tank Dumping So Important?

Improperly dumping your black water tank doesn’t just create unpleasant smells—it can damage your RV’s plumbing system, violate campground rules, and even pose health risks. According to the RV Safety & Education Foundation (RVSEF), over 40% of RV plumbing failures stem from incorrect tank maintenance.

Your 2020 Keystone Sprinter Limited 330KBS features a residential-style bathroom with a 38-gallon black water tank (per Keystone’s official specs). That’s generous capacity—but it also means more waste to manage responsibly.

💡 Pro Tip: Always dump your black tank after the gray tank. This uses soapy gray water to help flush out residual solids in the sewer hose—a trick many veteran RVers swear by.

Where Is the Black Water Tank Valve on the 2020 Keystone Sprinter 330KBS?

On your 2020 Keystone Sprinter Limited 330KBS, the tank valves are located on the driver’s side (left side when facing the front of the RV), near the rear axle. You’ll see two pull handles:

• Front handle: Gray water tank
• Rear handle: Black water tank

Both connect to a single sewer outlet port—standard on all Sprinter models from 2019 onward. The black tank valve is typically labeled or color-coded (often black or red) by owners for quick identification.

🔧 Note: If your handle feels stiff or won’t pull, don’t force it. Lubricate the valve stem with RV-safe silicone spray. Persistent issues may indicate a cable disconnect—a common problem in older Sprinters.

Step-by-Step Guide: How to Dump the Black Water Tank Safely

Follow these 6 precise steps every time you dump. Consistency prevents clogs and extends tank life.

1. Wear Protective Gear
   Always use disposable gloves and consider safety goggles. Black water contains harmful bacteria.
2. Connect the Sewer Hose Securely
   • Attach one end of your RV sewer hose to the RV’s outlet.
   • Ensure a tight fit using a bayonet-style or screw-on adapter.
   • Place the other end into the dump station inlet—pointing downward to avoid backflow.
3. Open the Gray Water Valve First (Optional but Recommended)
   Run your sink or shower for 1–2 minutes to send soapy water through the hose. This pre-lubricates the line.
4. Open the Black Water Tank Valve
   Pull the rear handle slowly. You should hear a gurgling sound as waste flows out.
   • Wait 5–10 minutes for complete drainage. Don’t rush it.
   • If flow stops early, close the valve, add 2–3 gallons of water + tank treatment, and let it sit for 30 minutes before retrying.
5. Flush the Tank (If Equipped)
   The 2020 Sprinter 330KBS includes a built-in tank flush system. Connect a garden hose to the labeled inlet (usually near the dump port), turn on water for 60–90 seconds, then close the black valve while water is still flowing to create a siphon effect.
6. Close Valves & Sanitize
   • Close black valve → disconnect hose → close gray valve (if open).
   • Rinse hose thoroughly and store in a sealed container.
   • Sanitize the dump station area with a bleach-water mix (1:10 ratio).

🌿 Eco Note: Never dump black water on the ground or into non-approved systems. It’s illegal in all 50 states and harmful to the environment. Learn more about proper waste disposal from the U.S. Environmental Protection Agency (EPA).

Common Problems & Fixes for 330KBS Black Tank Owners

Best Black Tank Treatments for Your Sprinter 330KBS

Not all treatments are equal. Avoid formaldehyde-based products—they harm septic systems and are banned in many campgrounds.

✅ Top 3 Recommended (2025):

1. Happy Campers Organic RV Tank Treatment – Enzyme-based, septic-safe, works in cold temps
2. Aqua-Kem Blue – Fast-acting, odor control lasts 5+ days
3. Green Gobbler RV Black Tank Deodorizer – Eco-friendly, dissolves paper and waste quickly

Use 2 oz per 40 gallons weekly, or 4 oz immediately after dumping for maintenance.

Maintenance Schedule: Keep Your Plumbing Problem-Free

• After every dump: Flush tank + rinse hose
• Monthly: Inspect valves, hoses, and seals for cracks
• Every 6 months: Replace sewer hose (UV exposure degrades plastic)
• Annually: Check roof vent cap and toilet seal (common leak points)

FAQ Section

Q1: Can I dump my black water tank at home?

A: Only if you have an approved residential sewer cleanout and local laws permit it. Many municipalities ban RV dumping into household systems due to grease and chemical buildup risks. Always check with your city’s public works department first.

Q2: How full should the black tank be before dumping?

A: Wait until it’s at least ⅔ full. Solids need liquid to flow out properly. Dumping too early leads to residue buildup and clogs.

Q3: Why does my black tank smell even after dumping?

A: Likely causes: a dry toilet P-trap, clogged roof vent, or residual waste in tank corners. Pour 1 gallon of water down the toilet, check the vent on your roof, and consider using a tank rinser.

Q4: Is it safe to leave the black tank valve open at a full-hookup site?

A: No. Always keep it closed. Leaving it open allows solids to settle in the hose instead of the tank, creating blockages. Only open it during active dumping.

Q5: How do I unclog a stuck black tank?

A: Try the ice-and-soap method: Add 5 lbs ice + 1 cup liquid dish soap + 2 gallons hot water. Drive for 15–20 minutes (the ice scrubs the tank walls), then dump. For severe clogs, use a tank auger or professional hydro-jet service.

Q6: Does the 2020 Sprinter 330KBS have a tank level sensor?

A: Yes—but they’re often unreliable due to waste buildup on probes. Don’t rely solely on the monitor. Use the “sound test”: tap the tank side with a coin; a hollow sound = empty, dull thud = full.

Conclusion

Mastering how to dump the black water tank in your 2020 Keystone Sprinter Limited 330KBS isn’t just about convenience—it’s essential for preserving your RV’s value, ensuring hygiene, and enjoying hassle-free adventures. With the right tools, routine care, and the steps outlined above, you’ll avoid 95% of common plumbing headaches.

🔧 Take action today: Bookmark this guide, share it with fellow RVers on Facebook or Reddit, and tag #Sprinter330KBS when you post your clean-dump success story! Your future self (and your nose) will thank you.

Safe travels, clean tanks, and happy camping! 🚐💨